Olive Oil Diet Research Articles

Influence of dietary fat quantity and composition on glucose tolerance and insulin sensitivity in rats

The hypothesis that dietary fat can influence glucose tolerance and insulin sensitivity adversely or beneficially was tested in rats fed diets supplemented with variable amounts and types of fat. Two concentrations of fat (10% and 20% by weight) diets were prepared and given to male Wistar rats for 5 weeks. The animals supplemented with high fat (20%) diets showed significant increase in body and visceral fat weights as compared to rats fed low fat (10%) diets. Only the rats supplemented with a diet containing 20% butter oil showed impaired glucose tolerance and insulin insensitivity compared to normal rats. However, rats fed olive oil diets had relatively normal glucose tolerance and insulin sensitivity, although they increased body weight and visceral fats in parallel with rats fed butter oil diets. Fish oil conferred protection against obesity induced by olive oil or butter oil diets and also markedly reduced the impairment in glucose tolerance and insulin sensitivity induced by butter oil. In conclusion, these results suggest that diet therapy with fish oil or olive oil may be useful for treatment of patients with impaired glucose tolerance and/or type 2 diabetes.

PC27 EFFECT OF OIL-SUPPLEMENTED DIETS ON LIVER EXPRESSION OF PPAR ALPHA-RELATED GENES IN PREGNANT RATS

Introduction: During late pregnancy, hypertriglyceridemia is developed. Although maternal triglyceridemia has been correlated to newborns weight, we have previously found that a hypotriglyceridemic drug like fenofibrate, was unable to reduce triglyceridemia in late pregnant rats but impaired fetal growth (1). These fibrates modulate the hepatic expression of genes related to lipid metabolism through the activation of the peroxisome proliferator-activated receptor alpha (PPARalpha). Since fatty acids have also been demonstrated to activate PPARalpha, we studied the effects of diets with different fatty acids compositions in pregnant rats on maternal triglyceridemia and the expression of PPAR related genes. Methods: Pregnant rats were fed a semi-synthetic diet containing 10% of either palm-, sunflower-, olive- or fish-oil throughout pregnancy. All the animals were killed on day 20. Pregnant rats that were fed standard pellet were also studied in parallel. Liver and blood were collected for later determinations following previously described methodology (2). Results: The expression of carnitine palmitoyltransferase (CPT-I), a PPARalpha target gene, was higher in those rats fed the different oil-supplemented diets as compared to those on pellets. These changes for CPT-I expression were related to those of plasma insulin and FFA levels. Rats fed either sunflower-or fish-oil diets showed higher apolipoprotein B expression than those fed palm- or olive-oil diets. Regarding genes related to lipogenesis, sterol regulatory element binding protein (SREBP1c) expression was higher in those rats fed any of the oil-supplemented diets except for the olive oil as compared to those fed pellets. On the contrary, the expression of fatty acid synthase (FAS) expression was lower in all the rats fed the oil-supplemented diets than those on pellets. The expression of stearoyl-CoA desaturase (SCD-1) was lower in rats fed sunflower- and fish-oil diets than in those fed either palm- or olive-oil. Similarly to the effect previously seen with fenofibrate in pregnant rats (1), the expression of the acute-phase protein, alpha2-macroglobulin, was reduced by all the oil-supplemented diets. These inter-group differences appeared similar to those found for maternal triglyceridemia. Conclusion: Changes in gene expression caused by the oil-supplemented diets indicate an enhanced fatty acid catabolism and decreased lipogenesis and acute-phase response, which would explain the significant reduction on triglyceridemia produced by the oil diets in pregnant rats.

Comparative effects of emu and olive oil on aortic early atherosclerosis and associated risk factors in hypercholesterolemic hamsters

The comparative cholesterol lowering and antiatherosclerotic properties of emu oil and olive oil were evaluated in four groups ( n = 8) of hamsters fed a nonpurified diet containing either 10% coconut oil crude and refined, emu oil, and olive oil and 0.05% cholesterol (wt/wt) for 8 weeks. Hamsters fed the olive and emu oil diets had significantly lower concentrations of plasma total cholesterol (−31%, and −25%; P < 0.05, respectively) and low-density lipoprotein cholesterol (LDL-C) (−50%, and −41%; P < 0.05, respectively) compared to the coconut oil–fed hamsters, with no significant differences in plasma high-density lipoprotein cholesterol (HDL-C) or triacylglycerol (TAG) concentrations. Compared to the coconut oil–fed animals, hamsters fed the emu oil and olive oil–containing diets had reduced aortic cholesterol ester concentrations (−20% and −60%, respectively). The present study suggests that compared to a diet containing coconut oil, both emu oil and olive oil are capable of reducing aortic early atherosclerosis in hypercholesterolemic hamsters.

Dietary fat type (virgin olive vs. sunflower oils) affects age-related changes in DNA double-strand-breaks, antioxidant capacity and blood lipids in rats

This study was designed to investigate the possible effect on DNA double-strand breaks, antioxidant capacity and blood lipids of feeding rats lifelong with two different dietary fat sources: virgin olive oil (rich in the monounsaturated oleic acid) or sunflower oil (rich in the polyunsaturated linoleic acid). No changes in mean or maximal lifespan were observed. Overall, aging led to increased levels of plasma cholesterol, triglycerides, phospholipids, total lipids, polyunsaturated fatty acids and DNA double-strand breaks. All these parameters were higher in animals fed on sunflower oil diet. Aging diminished total antioxidant capacity with both diets, but in a lower extension for virgin olive oil diet. A very good inverse correlation ( r=−0.715; P<0.01, for sunflower oil group and r=−0.535; P<0.01, for virgin olive oil group) between DNA damage and total antioxidant capacity was found. These results allow to conclude that dietary fat type should be considered in studies on aging, since the intake of oils with different polyunsaturation levels directly modulates total antioxidant capacity of plasma, DNA damage to peripheral blood lymphocytes and lead to important changes at the lipid metabolism level. In the present study best results were found after intake of virgin olive oil, which suggest the possible use of that edible oil to provide a healthier aging.

Bioavailability and antioxidant effects of olive oil phenols in humans: a review.

We reviewed the bioavailability and antioxidant effects of phenols from extra virgin olive oil. We searched the MEDLINE database for the years 1966-2002. To review the bioavailability of olive oil phenols, we selected animal and human studies that studied the absorption, metabolism, and urinary excretion of olive oil phenols. We also estimated the intake of the various phenols in the Mediterranean area. To review the antioxidant effects of olive oil phenols, we included human and animal studies on the effect of olive oil phenols on markers of oxidative processes in the body. We excluded studies without a proper control treatment and studies in which the antioxidant effects of phenols could not be disentangled from those of the fatty acid composition of olive oil. Bioavailability studies in humans show that the absorption of olive oil phenols is probably larger than 55-66 mol%, and that at least 5% is excreted in urine as tyrosol and hydroxytyrosol. Animal studies suggest that phenol-rich olive oil lowers oxidisability of ex vivo low-density lipoprotein (LDL) particles or lowers markers in urine of oxidative processes in the body. In five out of seven human studies, however, these effects of phenols were not found. There are no data on the phenol concentrations in plasma that are attainable by intake of olive oil. We estimated that 50 g of olive oil per day provides about 2 mg or approximately 13 micromol of hydroxytyrosol-equivalents per day, and that the plasma concentration of olive oil phenols with antioxidant potential resulting from such an intake can be at most 0.06 micromol/l. This is much lower than the minimum concentrations of these phenols (50-100 micromol) required to show antioxidant activity in vitro. Although phenols from olive oil seem to be well absorbed, the content of olive oil phenols with antioxidant potential in the Mediterranean diet is probably too low to produce a measurable effect on LDL oxidisability or other oxidation markers in humans. The available evidence does not suggest that consumption of phenols in the amounts provided by dietary olive oil will protect LDL against oxidative modification to any important extent.

Acceptability, Growth Performance and Cost Analysis of Diets Enriched with Lipids from Varied Plants and Animal Sources Fed to Fingerlings of &lt;i&gt;Clarias gariepinus &lt;/i&gt;(Teleostei, Clariidae) Burchell, 1822

The acceptability of diet, growth performance and cost benefit analysis of C. gariepinus fed varied diets enriched with dietary lipids from plant and animal sources was investigated. The acceptability of diets enriched with lipids was investigated using the “time to strike and acceptability index.” The growth potentials and survival of C. gariepinus fed varied dietary lipid, were investigated using “weight gain, specific growth rate and normalized biomass index.” The combined effects of diets fortified with either animal or plant lipids on diet acceptability, growth and survival of C. gariepinus, were studied. Furthermore, the cost benefit of feeding C. gariepinus fingerlings with diet enriched with varied lipid types was established. Results indicated that enrichment of C. gariepinus fingerlings diets with lipids enhances the acceptability of the diet, the best acceptable diet being olive oil enriched diet. The acceptability of diets enriched with olive oil, cow fat and pig fat were statistically not significantly different. Although, olive oil diets were easily accepted, with regards to weight gain, growth induction and survival the pig fat enriched diets performed best when compared with other lipid fortified diets. All lipid enriched diets had significantly different weight gain (p < 0.05), specific growth rate (p < 0.05) and survival rate (p < 0.05) than the control diet. Although lipid enhanced diets were better than those without lipid in C. gariepinus, animal lipid enriched diets had better acceptability index, weight gain, specific growth rate and survival than plant lipid fortified diets. The cost benefit analysis revealed that both pig and goat fats had better comparative and effective cost per unit weight gain. Key words: Diet, fingerlings, Clarius gariepinus Bio-Research Vol.1(2) 2003: 87-99

Olive oil and immune system functions: potential involvement in immunonutrition

Olive oil plays a crucial role as a main component of the Mediterranean diet, which has shown important benefits for the human health. According to the current knowledge, the administration of diets containing olive oil exerts some beneficial effects on the immune system functions due likely to the action of oleic acid rather than other substances contained in this fat. In the last few years, epidemiological, clinical and experimental studies have evidenced the potential of certain dietary lipids (containing polyunsaturated or monounsaturated fatty acids) as modulators of immune system functions due to their ability to suppress several functions of immune system in both humans and animals. As a result, these fats have been applied in the reduction of symptoms from diseases characterized by an overactivation of the immune system (autoimmune diseases) or in the reduction of cancer risk. Here, we review several relevant experimental and clinical data associated with the beneficial effects of olive oil upon the health, the mechanisms of action and the immune function susceptible of being be altered by the administration of dietary lipids and particularly of olive oil. In addition, we will also discuss the detrimental effects on the immune system functions caused by the administration of certain dietary lipids attributed mainly to a reduction of host natural resistance against infectious microorganisms as well as the involvement of olive oil diets in the regulation of immune resistance.

Dietary fat regulates mammary stearoyl coA desaturase expression and activity in lactating mice.

Mice in mid lactation (n=6 per group) were fed a control diet (1.19% fat), or diets containing safflower oil (25% w/w) or olive oil (25% w/w) for 7d. Mammary and liver stearoyl CoA desaturase (SCD) mRNA levels and mammary SCD activities were higher in lactating mice fed the control diet than in those fed the oil-supplemented diets. Further, mammary SCD mRNA was directly related to mammary SCD activity. Milk fat composition was influenced by dietary fat composition. The olive oil diet, high in 18:1, led to high levels of this fatty acid in milk and the safflower oil diet, high in 18:2, resulted in a milk fat with high levels of 18:2. These results show that there is regulation of SCD at the transcriptional level, associated with changes in enzyme activity and in milk fat composition.

Dietary-induced changes in the fatty acid profile of rat pancreatic membranes are associated with modifications in acinar cell function and signalling.

The effects of dietary lipids on the fatty acid composition of rat pancreatic membranes and acinar cell function were investigated. Weaning rats were fed for 8 weeks on one of two diets which contained 100 g virgin olive oil (OO) or sunflower-seed oil (SO)/kg. Pancreatic plasma membranes were isolated and fatty acids determined. Amylase secretion and cytosolic concentrations of Ca(2+) and Mg(2+) were measured in pancreatic acini. Membrane fatty acids were profoundly affected by the diets; the rats fed OO had higher levels of 18 : 1n-9 (42.86 (sem 1.99) %) and total MUFA compared with the animals fed SO (25.37 (sem 1.11) %). Reciprocally, the SO diet resulted in greater levels of total and n-6 PUFA than the OO diet. The most striking effect was observed for 18 : 2n-6 (SO 17.88 (sem 1.32) %; OO 4.45 (sem 0.60) %), although the levels of 20 : 4n-6 were also different. The proportion of total saturated fatty acids was similar in both groups, and there was only a slight, not significant (P=0.098), effect on the unsaturation index. Compared with the OO group, acinar cells from the rats fed SO secreted more amylase at rest but less in response to cholecystokinin octapeptide, and this was paralleled by reduced Ca(2+) responses to the secretagogue. The results confirm that rat pancreatic cell membranes are strongly influenced by the type of dietary fat consumed and this is accompanied by a modulation of the secretory activity of pancreatic acinar cells that involves, at least in part, Ca(2+) signalling.

Effect Of Dietary Olive Pomace Oil And L-Carnitine On Growth And Chemical Composition Of African Catfish, Clarias Gariepinus (Burchell, 1822)

The effects of dietary olive pomace oil and L-carnitine on growth performance, body indices and chemical composition of African catfish, Clarias gariepinus, were investigated. A 3x2 factorial design was used by offering diets having three different energy/protein ratios and supplemental L-carnitine at either 0 or 2000 mg/kg diet. Ten juvenile African catfish (12 g/fish) were stocked into 80-l glass aquaria and fed an experimental diet for seven weeks. The L-carnitine supple- mentation did not affect body indices. However, growth and chemical composition were influ- enced by both dietary lipid and L-carnitine. The increase in muscle lipid was greater than in the liver for all treatments. Fish fed the high energy diet (9% olive pomace oil) had a low appetite and feed intake, while fish fed the low energy diet (3% olive pomace oil) and supplemental L- carnitine had better feed intake and growth. On the other hand, fish fed the high energy diet (9% olive pomace oil) with or without L-carnitine had better feed conversion.

Monounsaturated n-9 fatty acids and adipocyte lipolysis in rats.

To investigate the role of the monounsaturated n-9 fatty acids (MUFA) in the lipolytic activity of adipocytes, a study was carried out in which an increase in MUFA was produced in the tissues by two different methods; by the dietary enrichment of oleic acid or by producing an essential fatty acid deficiency syndrome. For this, forty-five male Sprague-Dawley rats were fed with a normal-energy diet and were subdivided into three groups. The diets varied in the type of dietary fat; palmitic acid, olive oil, or soyabean oil+palmitic acid. At the end of the study measurements were taken of weight, plasma leptin, tissue concentration of fatty acids, fat-cell size in the epididymal and the omental adipose tissues, adipocyte lipolytic activity of both tissues after stimulation with adrenaline, and the capacity of insulin to inhibit lipolysis. The baseline and adrenaline-stimulated lipolytic activity were greater and the anti-lipolytic capacity of insulin lower in the animals undergoing an increase in MUFA in the tissues (palmitic-acid and olive-oil diets). The area under the curve of glycerol, used as an indicator of lipolytic activity, was positively correlated with the concentration of MUFA and negatively with polyunsaturated fatty acids in the adipose tissues. It is concluded that an increase in tissue MUFA, however obtained, induces an increase in lipolytic activity.

Modulation of EGFR and neu expression by n-6 and n-9 high-fat diets in experimental mammary adenocarcinomas

In this study we have investigated the influence of dietary mono- and polyunsaturated lipids on 7,12-dimethylbenz(alpha)anthracene (DMBA)-induced mammary tumorigenesis, and the modulation of expression of c-erbB1/EGFR and c-erbB2/neu as a mechanism of this influence. Two series of Sprague-Dawley rats were given a single dose of DMBA. Animals from Series 1 were fed a semi-synthetic low-fat or high-fat corn oil diet, following an initiation-promotion experimental design. Rats from Series 2 were fed low-fat or different high-fat diets (rich in corn oil or rich in olive oil) in the promotion stage of mammary carcinogenesis. High corn oil diet showed clearly a stimulatory effect on experimental breast carcinogenesis, suggesting a role of this kind of lipids on initiation and promotion of mammary tumorigenesis. Moreover, results suggested that olive oil acts as a negative modulator of the experimental breast cancer. On the other hand, two transcripts of EGFR and one neu mRNA were detected by chemiluminescent Northern blot in mammary adenocarcinomas. Analysis of data showed the tendency that high-fat corn oil diet decreases the 2.7 kb mRNA of EGFR, encoding a truncated form of the receptor with no enzimatic activity. High-fat olive oil diet increased EGFR mRNA levels, specially those from 2.7 kb, and decreased the relative abundance of neu mRNA. These data suggest that the modulating effect of dietary lipids on mammary carcinogenesis could result in changes of EGFR and neu mRNA, leading to an increase of EGFR activity by high-fat corn oil diet and a decrease of EGFR and Neu signal transduction pathway by high-fat olive oil diet.

Virgin olive and fish oils enhance the hepatic antioxidant defence system in atherosclerotic rabbits

Background & Aims: In this study we report the effects of sunflower, virgin olive and fish oils on the lipid profile and antioxidant defence system in liver mitochondria from rabbits with experimental atherosclerosis. Method: An atherogenic control group were fed for 50 days on a diet containing 3% lard and 1.3% cholesterol. Four groups were fed for an additional period of 30 days with a diet enriched in different oils: sunflower oil, virgin olive oil, refined olive oil and fish oil. A control group was fed with a standard chow. Results: The atherogenic diet caused important changes in the hepatic mitochondria lipid profile and in the enzymatic and non-enzymatic antioxidant defence system accompanied with an increase in the content of hydroperoxides in liver mitochondria. The administration of virgin olive and fish oils showed a better profile in the antioxidant system as well as decrease in the content of hydroperoxides. Conclusions: The intake of cholesterol- and lard-enriched diet leads to a high impairment in the hepatic antioxidant defence system. However, the replacement of that diet by other unsaturated fat-enriched diets using virgin olive, sunflower and fish oil enhances hepatic antioxidant defence system, virgin olive and fish oil diet provide the best results.

Plasma lipoproteins in transport of silibinin, an antioxidant flavonolignan from Silybum marianum

To assess the role of plasma lipoproteins in the transport of silibinin, an antioxidant flavonolignan, (125)I-labelled silibinin ((125)I-SB) administered perorally to the rat was used. The plasma (125)I-SB derived radioactivity was distributed among plasma lipoproteins according to their lipophilicity (TAG-rich lipoproteins 30-40% > LDL 15% > HDL 5%), and in the fraction of d > 1.215 containing albumin and other proteins a minority amount of radioactivity was found. Administration of (125)I-SB in a complex with phosphatidylcholine resulted in proportionally higher radioactivities in all fractions as well as in tissues. Dietary olive oil had a slightly decreasing effect on plasma concentrations of silibinin measured by HPLC as well as on (125)I-SB derived radioactivity in plasma and liver. In the TAG-rich lipoprotein fraction and HDL no effects of olive oil on the levels of (125)I-SB derived radioactivities were observed, however, at a 30 min interval the levels of (125)I-SB derived radioactivity in LDL and the heart were significantly decreased in the olive oil group. These results suggest that (i) silibinin is not resorbed by the chylomicron pathway, and (ii) the endogenous lipoprotein pathway VLDL --> LDL may play a role in the transport of silibinin from the liver to the extrahepatic tissues concurrently facilitating the lipoprotein antioxidant influence of silibinin.

Effect of Type of Grain and Oil Supplement on the Performance, Blood Lipoproteins, Egg Cholesterol and Fatty Acids of Laying Hens

The effects of type of grain (wheat vs. sorghum) and oil supplement/kg diet [0, 20g olive oil (OL), 20g safflower oil (SO), 10 g OL plus 10 g SO (OLSO)], over a 12-week period on the performance, plasma and lipoproteins lipids [cholesterol (C), triglycerides (TG), phospholipid (P)], and yolk C and fatty acids concentrations of laying hens were studied. Hens fed on the sorghum diet had significantly (P<0.05) higher yolk oleic acid concentration and oleic:linoleic acid ratio and plasma TG concentration in the low density plus high density lipoproteins (LDL plus HDL) fraction when compared with hens fed on the wheat diet. Birds fed on the OL diet had significantly (P<0.05) higher yolk oleic acid concentration and oleic:linoleic acid ratio, and plasma TG concentration in the VLDL fraction and lower plasma TG concentration in the LDL plus HDL fraction (P<0.01) when compared with those fed on the control diet. Hens fed on the SO diet had significantly (P<0.05) higher concentration of yolk linoleic acid and plasma lipids in the very low density lipoproteins (VLDL) fraction and lower yolk oleic:linoleic acid ratio and plasma TG concentration in the LDL plus HDL fraction (P<0.01) than hens fed on the control diet. Whilst, birds fed on the OLSO diet produced significantly (P<0.05) higher yolk unsaturated:saturated fatty acids ratio and lower palmitic and stearic acids concentrations when compared with those fed on the control diet. Dietary treatments did not significantly affect the weight gain, feed intake, rate of lay, egg and yolk weights, yolk lipid and C concentrations, daily C output, plasma total lipid concentration, plasma C and P concentrations in the LDL plus HDL fraction of hens. It was concluded that hens fed a sorghum based diet or a diet supplemented with olive oil produced eggs with high concentration of oleic and oleic:linoleic acid ratio and that hens fed a diet supplemented with safflower oil produced eggs with high concentration of linoleic and lower oleic:linoleic acid ratio and that hens fed a diet supplemented with olive plus safflower oils produced eggs with high concentration of unsaturated:saturated fatty acid ratio and lower palmitic and stearic acids.

Iron status in association with cardiovascular disease risk in 3 controlled feeding studies

The role of body iron stores in free radical-induced peroxidation and cardiovascular disease risk has been debated, but controlled feeding studies using measurements of non-transferrin-bound iron (NTBI) and LDL oxidation have not been conducted. We tested the hypothesis that NTBI and other measures of iron status do not affect oxidative susceptibility in healthy subjects with normal iron status. Plasma samples were analyzed from 77 healthy men and women aged 20-65 y who participated in 3 controlled feeding studies in which the type and amount of dietary fat were controlled. Iron status and in vitro LDL oxidation were assessed at baseline and at the end of each feeding period (4-8 wk). No significant relations were found between any measure of iron status (ferritin: 83 +/- 8.9 micro g/L; iron: 20.9 +/- 5.4 micro mol/L; TIBC: 74.4 +/- 11.0 micro mol/L; NTBI: 0.184 +/- 0.15 micro mol/L) and the in vitro measures of LDL oxidation (total dienes: 485 +/- 55 micro mol/mg LDL protein; lag time: 51.7 +/- 15.9 min; and rate of oxidation: 25.4 +/- 6.8 micro mol dienes.min(-1).g LDL protein(-1)). Equal-iron peanut butter-based diets were associated with higher plasma iron in men (22.4 +/- 3.8 micro mol/L) than was the olive oil diet (17.7 +/- 4.5 micro mol/L) (P = 0.02), but this slight elevation did not alter LDL oxidation. Diet composition may affect plasma iron in men, but LDL oxidative susceptibility is unaffected by the subtle variation in iron status. Thus, the results do not support a relation between iron status and LDL oxidative susceptibility, a possible risk factor for cardiovascular disease.

Effects of fish oil- and olive oil-rich diets on iron metabolism and oxidative stress in the rat.

The objective of the present study was to examine the effects of fish oil (FO)- and olive oil (OO)-rich diets on Fe metabolism and oxidative stress. Rats were fed for 16 weeks with diets containing 50 g lipids/kg; either OO, maize oil (MO) or FO. OO or MO diets contained a standard amount (100 mg/kg) of all-rac-alpha-tocopheryl acetate. FO diets were supplemented with 0, 100 or 200 mg all-rac-alpha-tocopheryl acetate/kg (FO-0, FO-1 or FO-2 diets, respectively). At the end of the feeding period, we measured non-haem Fe stores in liver and spleen, and erythrocyte and reticulocyte count. We also determined antioxidants and products derived from lipid peroxidation in plasma and erythrocytes. Our results showed reduced non-haem Fe stores in rats fed any of the FO diets. Reticulocyte percentage was higher in the rats fed FO-0 and FO-1. Plasma alpha-tocopherol was very low in rats fed the FO-0 diet. Rats fed the FO-1 and FO-2 diets showed higher alpha-tocopherol in plasma than the FO-0 group but lower than the MO or OO groups. We did not observe such differences in the alpha-tocopherol content in erythrocyte membranes. Superoxide dismutase and glutathione peroxidase activities were lower in the erythrocytes of rats fed the FO-0 diet. The products derived from lipid peroxidation were also higher in the FO groups. The administration of FO-rich diets increased lipid peroxidation and affected Fe metabolism. On the other hand, the OO-rich diet did not increase oxidative stress and did not alter Fe metabolism. Based on these results, we conclude that FO supplementation should be advised carefully.

Transplacental effects of high fat diets on functional activity of the spleen and lymph nodes, cell kinetics and apoptosis in mammary gland tumors in female rat offspring

We studied whether feeding pregnant female rats different high fat diets affects structural zones in the spleen and lymph nodes, involved in production of T and B cells, as well as cell kinetics and apoptosis in some offspring with mammary glands tumors. Rat mothers were fed either a 7% or 15% corn-oil or a 7% or 15% olive-oil diet. At four weeks of age, female offspring (n=10-15 per group) were transferred to 7% corn oil diet. Five-week old offspring were exposed twice to the carcinogen, dimethylbenz(a)antracene (10 mg/rat/week). Three months later, tumors were counted and sized, and samples from the spleen, axillary lymph nodes and tumors collected for immunohistochemical analyses. Feeding the mothers with both the 7% and 15% olive-oil diets significantly increased the number of tumor-free rats in offspring. Tumors were characterized with active mitosis, intensive lymphoid infiltration inside a knot and high rates of apoptosis, particularly in tumors obtained from rats whose mothers were fed the 15% olive-oil diet. In the spleen, the 15% olive-oil diet significantly increased the areas of the follicles and germinal centers but only in tumor-free rats. In tumor-bearing rats, areas of germinal centers increased compared to the 7% olive-oil diet. The 15% olive-oil diet increased all areas of the lymph nodes in tumor-free rats, while in tumor-bearing rats, this diet increased the areas of the cortex and mantle layer. We conclude that exposure to various diets in utero and during lactation affects the immune system. In addition, the promotion of apoptosis may play a key role in the mechanisms involved in the transplacental effects on mammary tumor development as seen using a 15% olive-oil diet, similar to the high fat diets of Mediterranean countries.

Influences of Olive Oil and Ghee (samen balady) on Serum Cholesterol of Jordanians

The effects of olive oil (OO) and ghee types (semen balady) on the serum lipid profile were studied in healthy volunteers (11 males, aged 36-44 year; 13 females aged 27-35 year). The 24 subjects ate their habitual diet with OO or ghee of cow milk fat (CMF), ghee of goat milk fat (GMF) or ghee of sheep milk fat (SMF) for 4 wk with 4 wk interval between the four diets. Compared with initial values, OO diet significantly (P<0.05) reduced concentrations of serum total cholesterol (TC, -3.42%) and low density lipoprotein cholesterol (LDL-c, -4.31%). OO caused slight reduction in concentration of high density lipoprotein cholesterol (HDL-c, -2.86%), and ratios of TC/HDL-c and LDL-c/HDL-c. Whereas ghee types significantly (P<0.05) increased these parameters and the SMF resulted in the highest rise of TC (+11.93%) and LDL-c (+16.16%). The highest rise in concentration of HDL-c (+8.81%) was shown with GMF. Ghee types slightly increased the ratios of TC/HDL-c and LDL-c/HDL-c compared with the initial values. SMF resulted in the highest rise of TC/HDL-c (+0.26) and LDL-c/HDL-c (+0.31) Serum triglycerides level increased (+3.38 %) after OO diet, whereas reduced (about -2.15%) after periods of ghee types. In general, the responses in serum lipids were greater in males than in females in all the four diets.

Effects of a high olive oil diet on the clinical behavior and histopathological features of rat DMBA-induced mammary tumors compared with a high corn oil diet

Effects of a high virgin olive oil diet on the promotion stage of dimethylbenz(alpha)anthracene-induced mammary carcinogenesis in rats were investigated in comparison with those of a high corn oil diet. Animals were randomly placed into 4 groups: control, fed a normolipidic control diet (3% corn oil); M, fed a high corn oil diet (20%); O, fed a high olive oil diet (3% corn oil plus 17% olive oil); and MO, fed the high olive oil diet after 33 days of high corn oil diet. Whereas the high corn oil diet clearly stimulated the mammary carcinogenesis, reducing the latency time and increasing the tumor incidence, multiplicity and volume, the high olive oil diet led to a lower tumor incidence than in the former group, a latency time similar to that of the control and lower tumor multiplicity and volume even than in the control group. Moreover, the histopathological features of the adenocarcinomas in olive oil groups were compatible with a greater degree of differentiation. These data suggest that the high virgin olive oil diet would have acted as a negative modulator of the experimental mammary carcinogenesis conferring to the tumors a more benign clinical behavior and a lower histopathological malignancy in comparison with the control and high corn oil diets.